Such an engine, particularly, although not exclusively, appropriate for propelling the upper stage of such a space launcher, is described for example in document AIAA 2001-3692 “Innovative Upper Stage Propulsion Concepts For Future Launchers” issued at the time of the 37th AIAA/ASME/SAE/ASEE JPC Conference and Exhibition held from Jul. 8 to 11, 2001 in Salt Lake City (Utah, USA).
The essential structural features of this aerospike engine are that such engines have a central spike and means generating pressurized gaseous flow, sending this flow onto the surface of said central spike. This central spike is coaxial with the longitudinal axis of the engine and comprises a functional lateral surface at least approximately in the shape of a cone, the base and the vertex of which are arranged respectively at said engine end and at the opposite end to said engine. For their part, said means of generating pressurized gaseous flows consist of a plurality of individual generators distributed around the axis of the engine, near the base of said central spike, so that the gaseous flows from said individual generators strike said lateral surface of the central spike.
Of course, the thrust of such an engine is the result of the application, to said functional surface of the spike, of the pressure exerted by said gaseous flows, and the larger this functional surface, the higher this thrust will be, which means that, for a given engine, the longer the spike, the greater the thrust. This results in a high-performance aerospike engine of significant longitudinal size, something which is highly undesirable in the domain of space.